METAIRIE, La. -- It didn’t take long for the New Orleans Saints' defense to erase the good vibrations it had generated with its dominant preseason performance.

In fact, it took just one play for the Saints to fall back into some of their old woeful ways in Monday night's season opener.

The Saints had just 10 men on the field for their first play in the 29-19 loss to the Minnesota Vikings.

The Saints' inability to force turnovers hurt them in Monday night's loss to the Vikings, including failing to come up with an interception on this play when A.J. Klein collided with Cameron Jordan. Brad Rempel/USA TODAY Sports

“We had it initially as a nickel call, and we ended up with just two corners instead of the third corner,” explained coach Sean Payton, who was asked if that was a frustrating way to set the tone for the season.

“To say the least,” Payton replied.

Fortunately for the Saints, that snafu didn’t come back to bite them too much, since they only allowed a 4-yard pass on that play. But there were plenty of other breakdowns in their pass coverage, pass rush and eventually their run defense throughout a painfully long night.

“Obviously it was a lackluster performance, and I think a lot of it was self-inflicted,” said new linebacker/signal-caller A.J. Klein, who pointed to a variety of issues, from the early penalties to the coverage breakdowns to the lack of pressure on blitzes to the missed opportunities for turnovers (once when he lunged for a ball in the air and crashed into defensive end Cameron Jordan in the process).

“We just have to be better overall. There’s no way to get around it,” Klein said. “It’s just the performance wasn’t good enough, and we’re gonna learn from this tape. There’s nothing else I can say. The score says it all.”

The Vikings had nine pass plays of 18'yards or more and two other passes that went for touchdowns, starting with a three-play touchdown drive that broke the game open in the second quarter (completions of 35, 21 and 18 yards).

A closer examination of those 11 plays showed no one common theme. The Saints got torched at least twice when they blitzed with six men, at least twice when they blitzed with five, at least four times with a four-man pass rush and at least once when they rushed only three. They also got burned badly on a play-action fake for that first 18-yard touchdown to receiver Stefon Diggs, when both cornerback De’Vante Harris and Vaccaro bit on the run fake.

The Saints had at least two obvious assignment breakdowns in zone coverage where nobody chased the open man. They had at least two plays where Diggs made a great contested catch against Harris. They had at least two plays where cornerback P.J. Williams appeared to allow too much cushion (though it’s unclear if it was man or zone). And they had one play where Bradford exploited a mismatch with receiver Adam Thielen against linebacker Manti Te’o -- even though there were eight men in coverage.

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Rookie first-round draft pick Marshon Lattimore wasn’t obviously beaten in any one-on-one matchups, though he appeared to be involved with one or two zone-coverage issues.

“It wasn’t a good tape,” Payton said. “I thought defensively we struggled in coverage at times. ... There were some MEs [mental errors], some poor decisions, overall not good enough.”

Payton said even though it’s a short week now for the Saints to prepare to host the New England Patriots, quarterback Tom Brady and one of the NFL’s most dynamic offenses, the team will take plenty of time to review the Minnesota tape first.

“We’re gonna make sure we see this tape, now. This isn’t one we just put away and move on to New England,” Payton said. “So that might be a little longer practice times. But there are enough things that we’ve gotta clean up that we’ve gotta see this. ... We can’t allow some of those mistakes to happen again.”

Vaccaro, who said the defensive backs would come in on their off day Tuesday to watch tape together, shouldered the blame for mistakes made by himself and others, since it’s his responsibility to prepare them as a veteran leader of the secondary.

And he said they need to “prepare two times more than” the Patriots to be ready for such a dynamic opponent.

“If we let these things slip into the next game, it’ll be even worse with an explosive offense like the Patriots,” said Vaccaro, who said he wasn’t quite ready to give up on the optimism that had been built up throughout this preseason.

“It’s painful. But at the same time, it’s early. Now if you ask me two, three, four, five weeks in and it’s still happening ...” Vaccaro said, not finishing the thought. “Because sometimes you have one of those games -- every team does; you saw the Patriots in Week 1 [have a bad game on defense] -- where everything’s not connecting, it’s not perfect. So I’m hoping and praying that was the problem and we can correct this film and move on.”